1. Field of the Invention
The present invention relates to a bag, and more particularly to a bag equipped with a bottom case, which is comprised of a bottom plate and a side peripheral wall and which is provided at its inner or outer surface with handle holding members and at its outer surface with caster mounting members, both which are injection molded therewith, in which the bottom case is coupled to an upper case made of fabric material or synthetic resin.
2. Description of the Prior Art
Among conventional kit bags and bowling bags, there is a bag integrally formed with a bottom case, which is designed such that the bottom case is comprised of a bottom plate and a side wall integrally formed at a periphery of the bottom plate to afford a receiving space therein, and is integrally formed at its outer surface with caster mounting members for supporting fixed or rotatable casters and at its inner surface with handle holding members by an injection molding process, and the bottom case is coupled to an upper case. Such bags are disclosed in Korean Utility Model No. 102353, Korean Patent Application No. 2001-0009210 and U.S. Pat. No. 5,607,175.
Bags disclosed in the above cited applications and patent have disadvantages as follows.
Since an upper case of the bag is usually made of cloth material and coupled to a side wall of a bottom case by sewing, when any one of the bottom case and the upper case is dirtied owing to its prolonged use, both the bottom and upper cases must be cleaned, and when any one of the bottom and upper case is damaged or broken, the bag itself must be discarded.
Furthermore, where the bottom case is increased in its height at its side wall without compensation of its thickness corresponding to the increment of height and coupled to an upper case, the side wall of the bottom case is easily squeezed or deformed.
To overcome this problem, the applicant had previously filed a patent application, in which protruded wall portions are formed at a side wall of a bottom case at a certain spacing such that fitting grooves are defined between the protruded wall portions and the side wall, and a shock absorber member is fitted in the grooves, thereby enhancing strength of the bag and preventing damage or breakage of articles received in the bag.
However, the bag proposed by the applicant has disadvantages in that the bottom case of the bag becomes complicated in structure and reduces productivity, and suffering early wear of the shock absorber.
Moreover, the bag is configured such that caster mounting members are provided at an outer surface of the bottom case. In this case, to facilitate attachment of casters, additional stoppers are produced and assembled to the caster mounting members followed by attachment of casters. However, such production and assembly of additional stoppers causes the entire manufacturing process to be complicated, resulting in reduction of productivity.
According to the bag disclosed in the application of the applicant, handle holes and circular or polygonal handle holding pipes are integrally formed at the bottom case so that an extensible handle can be inserted into the handle holding pipes through the handle holes. Where an extensible handle is assembled to a bottom case of a bag as in this case, there is a limit to various modifications to be made according to various applications of the bag. For example, a receiving space of the bag is reduced, and there are many restrictions in enlargement of the space and variety of designs.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a bag having a bottom case, which can be detachably coupled to an upper case to allowing only one case of both cases to be separated from the other case to be cleaned or replaced with new one.
Another object of the present invention is to provide a bag having a bottom case, which is provided at its side wall with a reinforcing frame to prevent the side wall from being squeezed or broken.
A further object of the present invention is to provide a bag having a bottom case, which is provided with handle mounting members to be integrally formed thereto or to be separated therefrom so as to diversify design and appearance of the bag.
In order to accomplish the above object, the present invention provides a bag comprising: a bottom case including handle holding members, caster mounting members and a side wall of a certain height, all of which are integrally formed therewith; an extensible handle adapted to be held by the handle holding member; two or more casters coupled to the caster mounting member; and an upper case detachably coupled to the bottom case by means of a slide fastener.
The bag may include a binding strip connected at its opposite ends to the bottom case and the upper case so as to share load acting on the slide fastener.
The bottom case may be provided at its inner surface with protruded wall portions such that fitting grooves are formed between the side wall and the protruded wall portions, in which a reinforcing frame made of metal or synthetic resin having a plurality of holes are fitted, the reinforcing frame being fixedly attached to the side wall by means of screws, thereby providing structural stability to the side wall.
The reinforcing frame may be provided with a reinforcing sub-frame and a partition so as to improve structural stability of the reinforcing frame and to provide various receiving spaces.
The caster mounting members may be integrally formed with stoppers and provided at an outer surface of the bottom case, and the bottom case is integrally formed at its outer surface with caster frames.
Each of the handle holding members may be a polygonal pipe segment such that its outer surface portion is opened and a spacing defined between the opened ends is smaller than a spacing defined between its root walls.
The handle holding members may be integrally formed at an inner surface of the bottom case.
The bottom case may be formed at its front side wall with handle holes, and the bottom case may be formed at both sides of a lateral middle line and at both sides of a rear end with front and rear pairs of handle holder holes, wherein the bottom case is formed with screw holes such that the screw holes are positioned between the front pair of handle holder holes and between the rear pair of handle holder holes, respectively.